Ski

ABSTRACT

The invention relates to a ski, especially a downhill ski, and a trimming rod for such a ski. The ski comprises an elongate ski body and a gliding surface on the bottom face of the ski body. The ski is characterized by at least one approximately longitudinally extending recess and/or one or more receiving devices for detachably receiving a trimming rod. The flexural stiffness and/or the weight of the ski can be adjusted by inserting different trimming rods, thereby allowing to adapt the handling characteristics of the ski to the skier. The ski can also be provided with one or more damping elements.

The present invention relates to a ski.

Usually skis have a ski body, provided on the underside with a sliding surface and steel edges. The upper side of the ski body is covered by a decorative coating. A ski body has a core made of wood and/or plastic and/or metal, with one or more lower belts on its underside and one or more upper belts on its upper side, to give the ski the desired flexural and torsional stiffness.

DE 27 53 608 C2 discloses a ski formed of two core elements superimposed on one another, with an intermediate belt between the two core elements.

DE 27 13 608 A1 describes a ski in which friction fibres for damping vibrations are movably embedded in and encompassed by adjacent material.

Known from DE 44 02 669 A1 is a ski with damping areas. These damping areas are formed on fastening areas for fastening the ski binding. The damping areas are provided on the upper side of the ski and encompassed by the upper belt.

DE 10 2004 002 897 A1 discloses another ski, with a core made of polyurethane foam in which reinforcing layers are embedded.

DE 102 36 152 A1 discloses a ski and ski binding combination in which a flat belt-like long section on the ski is located above the neutral bending plane. This long section is connected to the ski at one point by a pin and acts with one end on a damping device. When the ski bends, a pull or a thrust is exerted on the damper, thus damping the bending movement of the ski. This long section may also be provided in a rail integrated in the ski. This long section is flexible in design, but may however transmit quite strong tension and shear forces in the axial direction.

CH 554 178 A discloses a ski with a device for varying the flexibility of the ski. For this purpose several metal or plastic profile rods are embedded in the ski body, to which they are anchored at their front end close to the tip of the ski. Provided at the rear end is a tensioning device through which the profile rods may be tensioned. This is intended to make it possible to change the flexural stiffness of the ski.

DE 297 09 403 U1 describes a damping system for skis or snowboards, with mechanical friction elements securely fixed to the body of the ski or snowboard where they create friction which is intended to dampen bending movements. The friction elements are preferably embedded in the body of the ski or snowboard. The surfaces of the friction elements may be provided with layers of rubber-elastic material or also of material with good sliding properties.

EP 0 492 658 A1 discloses a binding plate which is located between a ski and the binding toe-irons. This plate has a freely sliding plate element 103, connected securely at one end to the ski. On deflection of the ski, the exposed end of the plate element therefore moves relative to the surface of the ski. This exposed end of the ski is located adjacent to a stop, so that the bending movement of the ski is limited in the area of the binding. In particular the position of the stop may be changed, so that by this means, different bending limits may be set for the ski.

The running properties of a downhill ski are determined mainly by its bending stiffness, its torsional stiffness and its sidecut. A strong sidecut permits the skiing of tight curves on the edge, with the ski bent into the curve by the sidecut. At the same time, though, the bending of the ski is also substantially influenced by the bending stiffness of the ski.

It has long been known that, in deep snow or on soft pistes, skis with low bending stiffness are more agreeable to use than skis with high bending stiffness. On hard pistes on the other hand, skis with high bending stiffness are preferred. On hard pistes at high speed, the forces acting on the ski are considerably higher than on soft pistes. In addition, the desired bending stiffness of the ski depends very much on the body weight, the skiing technique and the power of the skier using the skis. In racing, therefore, skis specially matched to the characteristics of the skier are used. The bending stiffness of the skis is measured by a three-point test, and suitable skis are chosen depending on the characteristics of the racer (weight, power, technique). Racers generally have several pairs of skis for each discipline (downhill, Super-G, giant slalom, slalom), with ski bodies and covers matched to different piste conditions.

The invention is based on the problem of creating a ski, in particular a downhill ski, with a bending stiffness which may be varied.

The problem is solved by a ski with the features of claim 1. Advantageous developments of the invention are set out in the dependent claims.

The ski according to the invention has an elongated ski body and a gliding surface on the underside of the ski.

The ski is distinguished by the fact that the ski body is provided with at least one recess running roughly axially and/or one or more support devices distributed in the axial direction of the ski for the releasable mounting of a trim rod with predetermined bending stiffness.

The axially running recess plus one or more support devices provided in combination with such a recess, or several support devices distributed in the axial direction of the ski have the effect that the trim rods are coupled to the ski at a minimum of three points distributed along the longitudinal axis of the ski. By this means the bending stiffness of the trim rod is added to the permanent bending stiffness of the ski body in the area in which the trim rod is coupled to the ski.

Through the insertion of a trim rod into the recess or support devices of the ski, its bending stiffness may be varied considerably. By replacing different trim rods or omitting a trim rod, the ski may be matched to the individual requirements of a skier, in particular to his weight, piste conditions and skiing technique. This is especially advantageous in combination with a sidecut in the ski since, when the ski is set on edge, the bending stiffness influences the deflection caused by the sidecut.

The recess is preferably in the form of an elongated hollow channel with a constant cross-section, with the hollow channel defined by a plastic or metal tube or formed directly in the material of the ski body. The cross-section of the hollow channel may be circular, elliptical, oval, rectangular or square. Preferably the hollow channel is higher than it is wide, so that a trim rod fitting positively into the hollow channel has greater stiffness in the vertical than in the horizontal direction.

The tube defining the hollow channel is embedded integrally in the ski body. The ski body usually has an upper belt, and the hollow channel may be located either below or above the upper belt.

Preferably at least two hollow channels are provided, with one of the hollow channels above and the other below the upper belt. The vertical displacement of the two hollow channels gives considerable stiffening to the ski when suitable trim rods are inserted in both hollow channels.

The trim rod is an elongated body fitting positively into the recess of the ski. In the present invention, the term “fitting positively” is taken to mean a fit with sufficient play to enable the trim rod to be inserted into and removed from the recess. However, no more play than is required for the insertion and removal of trim rods should be provided.

The trim rod may be made of a fibre-reinforced plastic which as a rule will have a high level of rigidity. Typical materials are fibre-reinforced plastic and metals such as e.g. aluminium or titanium. The trim rod may be made of rigid material over its entire length. It may however be expedient to make sections of it from materials with different bending stiffness.

Preferably the trim rod is provided with a sheath of soft elastic material, e.g. rubber. This soft elastic material generates a high coefficient of friction, which effectively dampens high-frequency vibrations. The entire length of the trim rod or sections of it may also be made of a heavy material, e.g. lead or tungsten, in order to increase the weight of the ski over its full length or over sections of it.

A further problem of the invention is to create a ski, in particular a downhill ski, with better running properties than those of conventional skis.

The problem is solved by a ski with the features of claim 28. Advantageous developments are set out in the related dependent claims.

This ski has a ski body, and a binding plate mounted on the ski body, which is coupled to the ski by means of a firm-loose mounting.

This ski is distinguished by the fact that the binding plate is provided with a damping element which is coupled to the ski body via a lever mechanism, and which converts a change in the difference in height between the ski body and the binding plate into a horizontal translatory movement. Also the damping element is so fitted to the binding plate as to counteract the translatory movement. This provides very effective damping of differences in height between the ski body and the binding plate resulting from deflection of the ski.

Preferably the damping element is adjustable, so that the damping of the ski may be adjusted individually by the skier.

The invention is explained in detail below with the aid of the drawings which show schematically, and not to scale, in:

FIG. 1 a ski according to the invention, viewed from above

FIG. 2 a section through the ski of FIG. 1 along line A-A

FIG. 3 a trim rod

FIG. 4 the ski of FIG. 1 according to the invention in a side view together with a binding unit

FIGS. 5 a-5 d cross-sections of other skis according to the present invention

FIG. 6 a further ski according to the invention in a perspective view at an angle from above

FIG. 7 a cross-section through the ski of FIG. 6 in the area of the hollow channels

FIG. 8 a further ski according to the invention in a perspective view at an angle from above

FIG. 9 a detail of the ski of FIG. 8 in the blade area, in a perspective view, and

FIG. 10 a detail of the ski of FIG. 8 in the binding area, in a perspective view.

FIGS. 1 to 4 show, in a representation which is not to scale, an embodiment of the ski 1 according to the invention, together with a trim rod 11. The ski has an elongated ski body 2, which is provided at one end with a blade area 3 with an upturned ski tip. The ski has a central binding area 4 and a rear end section 5.

In the central binding area 4 the ski, viewed from above, is narrower than in the blade area 3 and the rear end section 5. This geometry is described as the sidecut.

Formed on the underside of the ski body 2 is a gliding surface 6 with steel edges 7 provided at the sides. The ski body 2 is covered by a decorative or covering surface.

The sidecut of the ski helps it to bend when set edgeways, which involves the blade area 3 and the rear end section 5 being bent slightly upwards compared to the central binding area 4. Preferably the bending is such that the edge 7 lying on the piste describes a segment of a circle, so that the ski travels round a curve without a slipping phase. The strength of the deflection and thus of the curve radius depend however not only on the sidecut of the ski, but also substantially on the forces involved and on the bending stiffness of the ski 1. The factors to be considered here are in particular the weight of the skier, the speed, and the position of the skier relative to the centre of the ski. If the skier's centre of gravity is a little in front of the middle of the ski, then the blade area 3 will be bent more sharply, while if the skier is more to the rear, then the rear end section 5 will be more strongly bent. The position of the skier over the ski depends greatly on his stance and his skiing technique.

The ski 1 shown in FIGS. 1, 2 and 4 has three recesses 8, running roughly in the longitudinal direction of the ski. The recesses 8 form elongated hollow channels with a constant, circular cross-section. They are each defined or bounded by a plastic or metal tube which is embedded in the ski body. The ski body has a wooden core 9, which has a lower belt on its underside and an upper belt on its upper side. A central hollow channel 8/1 is formed in the core between the upper belt and the lower belt. The central hollow channel 8/1 extends in a straight line from the rear end section 5 to the blade area 3.

The two other hollow channels 8/2 are located, viewed from above, in the edge section of the ski 1 above the upper belt. These hollow channels 8/2 also extend from the rear end section 5 to the blade area 3, where they follow the curvature of the sidecut of the ski.

The plastic tubes which define the hollow channels 8 are preferably made of fibre-reinforced plastic. They therefore already provide the ski 1 with considerable reinforcement, for which reason the strength of the upper belt and the lower belt may be somewhat reduced, as compared with conventional skis. Through the insertion of trim rods 11 in the hollow channels 8 it is possible to vary the bending stiffness of the ski 1. In particular by interchanging trim rods and trim bars of different bending stiffness, the bending stiffness of the ski may be varied considerably. Computer simulations have shown that the bending stiffness may be varied over a range of approximately 15%, with the bending stiffness being measured by the three-point bending test. The bending stiffness of all rods in total comes to around 5 Nm² to 150 Nm² and may be distributed over several rods. Preferably the overall bending stiffness of the trim rod(s) lies in the range of 10 Nm² to 100 Nm², and in particular in the range from 25 Nm² to 75 Nm².

The trim rods are preferably pultruded plastic rods with reinforcing fibres aligned only in the rod direction (uni-directional). The type and density of the fibres determines the stiffness of the trim rod. All known reinforcing fibres, e.g. carbon fibre, boron fibre, glass fibre and the like are suitable. The trim rod may also be made of a suitable metal, such as e.g. aluminium or titanium or suitable alloys. For technical production reasons it is expedient for the trim rod to be made as a solid body. If however a trim rod 11 is intended to be of low weight, then it may be expedient to make it in the form of a tube, in particular a titanium or plastic tube.

The trim rod 11 shown in FIG. 3 has a an end piece 9 with a threaded section 10 by means of which the trim rod 11 may be screwed into a corresponding threaded bushing (not shown) in the recess 8. The leading end of the threaded rod 2 lies freely in the hollow channel 8 so that, with the ski 1 under a bending load, it does not hit up against the front end of the hollow channel 8. The trim rod is thus fitted with one end freely movable in the longitudinal direction of the ski. This ensures freedom from strain between the trim rod 11 and the hollow channel 8.

Within the scope of the invention it is of course also possible the fix the trim rod 11 to the ski 1 in another way. The holding forces required for this purpose are in any case very low since, on account of the preload of the ski (see FIG. 4), the hollow channel 8 has a certain curvature so that the straight trim rod 11 is somewhat pre-stressed in the hollow channel 8 and a degree of fixing is provided by frictional contact.

With the trim rod according to the invention it is also possible to stiffen the ski in certain areas, by making sections of the trim rod 11 out of materials with different stiffness. Thus it is expedient, for a skier who leans well forward, to provide greater stiffness in the front part of the ski than in the back part of the ski. Accordingly the trim rod 11 is then made of a very stiff material in the front part, with a less stiff material at the rear. For skiers with a not very advanced technique it may be expedient to make the front and rear sections relatively soft, and to stiffen the central binding area 4. This makes it easy to bend the ski in the curve, while still lending the ski enough stiffness to give the skier security under harder piste conditions. In such a case it may be expedient e.g. to make the trim rod of a stiff material in the middle section, with the rear end section made of a non-fibre-reinforced plastic with less stiffness.

In racing on the other hand it may be sensible to use the trim rod according to the invention not only to adjust stiffness but also weight. This may be achieved for example by providing a heavy trim rod, e.g. made of lead or tungsten. It may however also be expedient to make sections of the trim rod 11 of a heavy material, with other sections made of materials with a high degree of stiffness. For racing it may be useful to provide a trim rod of heavy material in the central binding area 4, with on the other hand a trim rod of a highly rigid material in the front and rear sections.

As already described above, the hollow channels 8/2 are displaced a little upwards relative to the hollow channels 8/1. This vertical displacement of the hollow channels and the trim rods inside them gives the ski significantly greater stiffness than if all the hollow channels were arranged on the same plane. Since generally very high stiffness is desired in the central binding area 4 of a ski, it is also expedient to provide this vertical displacement in the central binding area 4, and to guide the upper hollow channels 8/2 towards the blade area 3 and in the direction of the rear end section 5 downwards into the plane of the middle and lower hollow channel 8/1.

In this way the trim rods 11 provide greater reinforcement in the central binding area 4 of the ski than in the front and rear end sections of the ski.

FIGS. 5 a to 5 d show simplified cross-sections through further embodiments of the ski according to the invention, each with a ski body 2, a gliding surface 6 and two steel edges 7. These ski bodies have two hollow channels 8 (FIG. 5 a) or one hollow channel (FIGS. 5 b to 5 d). The hollow channels may have a cross-section which is circular (FIGS. 5 a, 5 b), or rectangular (FIG. 5 c), oval (FIG. 5 d) or elliptical. The trim rods are made with a correspondingly matching cross-section. The fit lies in the range between 5/100 mm and 1/10 mm.

The above embodiments relate to a ski body 2 with a wooden core and a lower belt and an upper belt. The version of a ski according to the invention with a recess running in the longitudinal direction for the releasable holding of a trim rod may however also be used very advantageously for the individual stiffening of skis with a core made of plastic foam, in particular polyurethane foam. Such skis are described e.g. in DE 10 2004 002 897 A1, and may be produced very cost-effectively. With the hollow channels and trim rod according to the invention they also have the desired bending stiffness which is often lacking.

It may also be expedient to provide the trim rods 11 with an outer sheath of soft elastic material, such as e.g. rubber. This material creates considerable friction between the hollow channel and the trim rod 11 during the vibrating movement of the ski 1. By this means, high-frequency vibrations of the ski 1 are effectively damped. Such a soft elastic material is especially useful in particular in the central binding area 4 of the ski 1.

FIGS. 6 and 7 show a further embodiment of a ski according to the invention. This ski also has a blade area 3, a central binding area 4, a rear end section 5, a gliding surface 6 and two steel edges 7.

The ski has two recesses in the form of hollow channels 8, which extend slightly beyond the central binding area 4 of the ski. However, each of the hollow channels 8 ends before the front blade area 3 and before the rear end section 5, opening out above the surface of the ski in the blade area 3 and the rear end section 5 respectively. A trim rod 11 inserted in the hollow channel 8 therefore protrudes at both ends of the hollow channel, to lie freely above the blade area 3 and the rear end section 5 of the ski 1 respectively.

To fix the trim rods 11, bearings 12, 13 are provided in the blade area 3 and in the rear end section 5 of the ski 1. The bearings 12, 13 are metal parts with vertical through holes for fixing the bearings 12, 13 by means of screws into threaded bushings 14 embedded in the ski 1. In each case several threaded bushings 14 are distributed in the longitudinal direction of the ski, so that the bearings 12, 13 may be fitted at different positions on the ski.

The rear bearing 12 has two horizontal eyelets 15 to hold the rear end section of the trim rods 11. In the blade area a separate front bearing 13, each with a single eyelet 15, is provided to hold the front end section of the trim rod. An O ring is provided in each of the eyelets 15.

The eyelets 15 of the rear bearing 12 engage in corresponding grooves in the trim rods 11, so that the latter are fixed in the longitudinal direction of the ski 1. In the eyelets 15 of the front bearing 13, the trim rods 11 rest with some play, i.e. without fixing in the longitudinal direction. The trim rods are therefore freely movable in the longitudinal direction of the ski.

Since the bearings 12, 13 may be fixed at different positions in the longitudinal direction, it is possible to change the position of the trim rods relative to the ski 1 accordingly. In this way it is possible to provide the ski with greater bending stiffness at either the front or the rear, and to adjust the running characteristic of the ski to cater for a more forward or a more backward stance of the skier.

The ski body 2 of this ski has a shell 16 of fibre-reinforced plastic material, in particular carbon-fibre-reinforced material (FIG. 7). The two hollow channels 8 are formed in this shell. The trim rods 11 located in the hollow channels 8 in FIGS. 6 and 7 are tubular in shape. It is possible to insert more trim rods with a smaller outside diameter into the tubular trim rods 11. This gives further means of varying bending stiffness.

The structure of the core 2 may in principle be of wood and/or plastic and/or metal, as desired.

The ski 1 shown in FIG. 6 has a binding plate 17 integrated in the ski itself. The binding plate 17 is fitted with clearance above the surface of the ski body 2. It is joined to the ski by two rear support columns 18 and two front support columns 19. In each case, all support columns 18, 19 are connected to the ski body 2 by means of a swivel joint (not shown). The columns are able to pivot around the swivel joints for a short distance in the longitudinal direction of the ski. The rear support columns 18 are connected rigidly to the binding plate 17. The front support columns 19 are in turn connected to the binding plate 17 by a swivel joint 20. The front support columns thus form an upright rocker. The support columns 19 may therefore also be described as hinged supports. By this means, the bending line of the ski 1 is completely decoupled from the binding plate 17. This type of coupling of the binding plate 17 to the ski body 2 represents a firm-loose mounting of the binding plate 17 relative to the ski body 2.

Preferably the support columns in the ski body 2 are coupled to the ski body 2 in a bending-neutral zone by means of the swivel joints. If the ski body is made of an isotropic material, then the bending-neutral zone will be in the centre between the upper and lower sides of the ski body. If the ski body is made of an anisotropic material, then the bending-neutral zone will be correspondingly displaced upwards or downwards.

This coupling of the binding plate is very advantageous in combination with the design of the ski according to the invention with a recess to hold a trim rod, since by this means the individual setting of bending stiffness through the use of suitable trim rods may be effected in the optimal manner. This coupling of the binding plate to the ski, however, also represents an independent inventive concept.

In the embodiment shown in FIGS. 1, 2 and 4, the recess or hollow channel extends over approx. 70% to 80% of the overall length of the ski. In the embodiment shown in FIGS. 6, 7, the hollow channel 8 extends only over 40% to 50% of the length of the ski. In principle it is possible to fix the trim rod to the ski using only suitable bearings (see bearings 12, 13). It is however preferable to provide a hollow channel, at least in the binding area. Expediently the hollow channel extends over a length of at least 30% of the overall length of the ski, or at least 50% of the overall length of the ski, or at least 70% of the overall length of the ski.

Shown in FIGS. 8 to 10 is a further embodiment of a ski according to the invention. The basic structure of this ski corresponds to the ski of FIGS. 6 and 7, for which reason identical parts have the same reference number. They will not be explained again. The ski 1 according to FIGS. 8 to 10 differs from the ski according to FIGS. 6 and 7 through damping elements 21, 22, 23.

The damping elements 21, 22, 23 are hydraulic shock absorbers, cylindrical in shape, in which a piston is movably mounted. During this movement a fluid is forced through constriction points, which damps the movement of the piston. The piston is connected to an externally guided piston rod 24, 25, 26.

The damping effect of the damping elements 21, 22, 23 is preferably capable of being set, so that the damping of the ski may be adjusted individually by a skier. In particular an hydraulic oil used in the shock absorber may be temperature-dependent so that it is expedient to vary the damping effect according to the temperature. The damping effect is set by means of a handwheel 27 on the damping elements 21, 22, 23. The hydraulic oil used in the damping elements 21, 22, 23 is specially designed for low temperatures.

The front ends of the trim rods 11 are each coupled to a piston rod 24 of the damping elements 21 by means of ball joints. The damping elements 21 are elongated bodies, arranged on the ski 1 as straight-line extensions of the trim rods 11. The damping elements 21 are joined rigidly to the surface of the ski body 2 in the blade area 3 by means of two fastening devices 28. The fastening devices 28 are attached releasably to the ski body 2 by means of screws, and their position may be changed in the longitudinal direction of the ski.

At the rear end section 5 of the ski 1, corresponding damping elements 22 are coupled by means of ball joints through their piston rod 25 to the rear ends of the trim rods 11, and are attached to the surface of the ski body 2 by suitable fastening devices 29. Their position too may be changed in the longitudinal direction of the ski.

The damping elements 21, 22 thus form bearing elements to support the ends of the trim rods 11, with the ends being able to move in the longitudinal direction of the ski. The damping elements 21, 22 are relatively small and have a low displacement volume, so that they dampen effectively only under more rapid deflection of the ski.

In the present embodiment, the trim rods 11 are fitted with freedom to move in the hollow channels 8. If in running the ski undergoes bending in the blade area 3 or in the rear end section 5, then the distance between the damping elements 21, 22 reduces, causing the trim rods 11 to press the relevant piston rods 24, 25 into the corresponding cylinders. The bending up of the ski 1 in the blade area 3 or the rear end section 5 is thus dampened by the damping elements 21, 22. The same applies for the movement back into the original position, which is retarded by the damping elements 21, 22. This prevents uncontrolled vibration of the ski.

It may also be expedient to fix the trim rods 11 in the area of the centre of the ski or in the central binding area 4. The front half of the ski 1 is then damped only by the front damping elements 21, and the rear half of the ski 1 by the damping elements 22. For the running properties of the ski it is especially important that the front section of the ski is damped. It may therefore be sensible to provide only the front damping elements 21, and to fix the trim rods either in the area of the centre of the ski or in the central binding area 4, or else in the rear end section 5. Simulations have shown that, with the front damping elements 21, the first and second inherent mode of vibration of the ski is damped.

Also provided is the central damping element 23 which may be used in combination with the front and/or rear damping elements 21, 22, or on its own. The central damping element 23 is fitted in a recess 30 of the binding plate 17, from which it protrudes slightly upwards. This involves the damping element 23 standing around 2 cm above the top surface of the binding plate 17 in the area roughly midway between a front and a rear toe-iron of a binding (not shown). Since at the binding toe-irons, a support surface of predetermined height and the ski boot in the central area bulge outwards, ski boots of conventional design do not collide with the damping element 23.

The damping element 23 with its piston rod 26 is aligned roughly horizontally and pointing towards the blade area 3. The piston rod 26 protruding from the damping cylinder 32 of the damping element 23 has a length of a few centimetres (approx. 7 cm to 10 cm) and is fixed to the binding plate 17 by means of a swivel joint 31. The damping cylinder 32 has two retaining arms 33 extending from the side. The ends of the retaining arms 33 are each attached rotatably to a toggle joint 34. Each of the toggle joints 34 has two arms 35, 36 which enclose an angle of around 90° or a little more. At their apex, the toggle joints 34 are pivotably mounted by means of a swivel joint 37 in a side recess of the binding plate 17. The arm 35 of the toggle joint 34 extends roughly vertically upwards, with a retaining arm 33 fixed to its free end in each case. The shorter arm 36 extends from the swivel joint 37 towards the rear end of the ski in a roughly horizontal direction. The shorter arm 36 is approximately half the length of the longer arm 34.

At the free end of the shorter arm 36, one end of a coupling rod 39 is attached by means of a swivel joint 40. The other end of the coupling rod 39, which extends vertically downwards into the ski body 2, is pivotably mounted in the ski body 2.

If a ski end is bent upwards or downwards, then the ski body bulges down or up in the central binding area 4, relative to the binding plate 17, so that the distance between the ski body 2 and the binding plate 17 is increased or reduced. This vertical movement of the ski body 2 relative to the binding plate 17 is converted by the coupling rods 39 via the toggle joints 34 into a horizontal translatory movement of the damping cylinder 32. Here, due to the differing lengths of the arms 35, 36 of the toggle joint 34, the movement path of the coupling rod 39 is converted into the double movement path of the damping cylinder 32. The movement itself is damped by the damping element 23. Computer simulations have shown that this damping element 23 dampens vibrations of the first inherent mode very effectively. The movement of the damping cylinder 32 is not an exact translatory movement, but a movement along a curve due to the guidance of the arm 34.

Since with this damping arrangement, the distance between the ski body 2 and the binding plate 17 is converted into a translatory movement of the damping cylinder 32, a movement path of the damping cylinder 32 of approximately 10 mm to 15 mm is obtained during normal deflections of the ski. Movements with such amplitudes may be damped very effectively by hydraulic shock absorbers. This damping arrangement acts with the coupling rod 39 preferably around the mid-point between the rear support column 18 and the front support column 19 of the binding plate 17, so that a maximum movement path of the piston rod 26 and the damping cylinder 32 respectively is obtained.

The damping element 23 is preferably so designed that the movement between the piston rod 26 and the damping cylinder 32 (springing-in) caused by the increase in the distance between the binding plate 17 and the ski body 2 is more strongly damped than the movement in the opposite direction (springing-out). The springing-out is preferably not damped at all. The damping characteristic of the springing-in is preferably individually adjustable.

When the springing-in is damped, the deflection of the ski is damped at the start of the vibration, so that the ski is quickly damped at the onset of the vibration. At the end of the vibration, on the other hand, the spring effect of the ski is fully available to initiate fresh vibration. This property of the damping element is also described by the inventors as “soft landing”.

As already described above, the trim rods are preferably fixed at around their longitudinal centre. Fixing is effected for example by means of a pin 41, which is used to fix the coupling rod 39 to the ski body 2. The pin 41 extends through the whole of the ski body 2 and is held at each end by one of the two coupling rods 39. The pin 41 also extends through the edge section of the hollow channels 8, engaging positively in a corresponding recess in the trim rods 11. By this means the trim rods are fixed securely in the longitudinal direction. In principle, other means of fixing are also suitable, e.g. a bracket which may be clamped.

In the above embodiment, the trim rods 11 are coupled to the damping elements 21, 22 by a ball joint. Instead of ball joints, elastomer coupling elements may also be provided.

Within the scope of the invention it is also possible, instead of hydraulic shock absorbers as damping elements 21, 22, 23, to provide elastomer dampers or friction dampers, although hydraulic shock absorbers are preferred on account of their better damping properties.

The invention has been explained above with the aid of embodiments of a downhill ski. It is however also suitable for use for a cross-country ski, in particular a cross-country ski for skiing in the classical style. Such cross-country skis are waxed with grip wax in the middle section. For dry snow a hard wax is applied, and for very wet snow or an icy run a klister is used as grip wax. The hard wax is in principle applied over a longer section than the klister. When a klister is used, cross-country skis with greater stiffness are preferred than when a hard wax is used, since the klister should only come into contact with the snow or ice when the skier pushes off. Hard wax on the other hand may also be in contact with the snow during the gliding phase. By providing a recess according to the invention to accommodate a trim rod, a cross-country ski may be matched to the relevant snow conditions.

LIST OF REFERENCE NUMBERS

-   1 ski -   2 ski body -   3 blade area -   4 central binding area -   5 rear end section -   6 gliding surface -   7 steel edge -   8 recess/hollow channel -   9 end piece -   10 threaded section -   11 trim rod -   12 bearing -   13 bearing -   14 threaded bushing -   15 eyelet -   16 shell -   17 binding plate -   18 support column -   19 support column -   20 swivel joint -   21 damping element -   22 damping element -   23 damping element -   24 piston rod -   25 piston rod -   26 piston rod -   27 handwheel -   28 fastening device -   29 fastening device -   30 recess -   31 swivel joint -   32 damping cylinder 32 -   33 retaining arm -   34 toggle joint -   35 arm -   36 arm -   37 swivel joint -   38 recess -   39 coupling rod -   40 swivel joint -   41 pin 

1. Downhill ski comprising an elongated ski body and a gliding surface on the underside of the ski, wherein the downhill ski is sidecut; and the ski body is provided with several elongated hollow channels of constant cross-section extending in a lengthwise direction through the elongated ski body with a trim rod installed in each of the channels, wherein each of said channels is defined by tubes which are embedded integrally in the ski.
 2. Ski according to claim 1, wherein at least one end of the trim rod is mounted so as to be movable in the axial direction of the ski.
 3. Ski according to claim 1, wherein the channels extend over at least 30% of the length of the ski.
 4. Ski according to claim 1 wherein the cross-sections of the channels are circular, elliptical, oval, rectangular or square.
 5. Ski according to claim 1, wherein the sections of at least two of the channels are vertically displaced from one another.
 6. Ski according to claim 1, wherein the tube is made of fibre-reinforced plastic.
 7. Ski according to claim 1, wherein the channels are formed out of the material forming the ski body.
 8. Ski according to claim 1, wherein the channels are formed in a shell enveloping the ski body.
 9. Ski according to claim 8, wherein the material in which the channels are formed is a fibre-reinforced plastic material.
 10. Ski according to claim 1, wherein the bending stiffness of all trim rods in total comes to around 5 Nm² to 150 Nm².
 11. Ski according to claim 1, wherein bearings are provided as support devices for holding one or both end sections of a trim rod to the surface of the ski.
 12. Ski according to claim 11, wherein the bearings may be fixed at different longitudinal positions on the ski.
 13. Ski according to claim 1, wherein each trim rod is provided with a bearing which may be so brought into engagement with the trim rod that by this means the trim rod is fixed in its longitudinal position on the ski.
 14. Ski according to claim 1, wherein at least one end of the trim rod is coupled to the ski body by means of a damping element.
 15. Ski according to claim 14, wherein the damping element is an hydraulic shock absorber or an elastomer damper or a friction damper.
 16. Ski according to claim 1, wherein a core of the ski body is made of wood and/or plastic with an upper belt on its upper side, wherein the hollow channels are located above the upper belt of the ski body and the plastic core of the ski body is made of a plastic foam.
 17. Ski body for a downhill ski having a gliding surface on the underside of the ski body, wherein the ski body is sidecut, and the ski body is provided with several hollow channels extending in a lengthwise direction each for the mounting of a trim rod, wherein the hollow channels have a constant cross-section and each of said hollow channels is defined by a tube which is embedded integrally in the ski body.
 18. Ski body according to claim 17, wherein the structure of a core of the ski body is made of wood and/or plastic with an upper belt on its upper side, wherein the hollow channels are located above the belt of the ski body.
 19. Ski body according to claim 17, wherein the core of the ski body is made of a plastic foam.
 20. Ski body according to claim 17, wherein a shell enveloping the ski body is provided and the channels are particularly formed in said shell enveloping the ski body, and the material in which the channels are formed is a fibre-reinforced plastic material.
 21. Ski body according to claim 17, wherein the tube is made of fibre-reinforced plastic.
 22. Ski with a ski body, a binding plate mounted on the ski body and coupled to the ski by means of a firm-loose mounting, wherein the binding plate is fitted with a damping element coupled to the ski body through a lever mechanism which converts a change in the difference in height between the ski body and the binding plate into a horizontal translatory movement, and the damping element is mounted on the binding plate in such a way as to counteract the translatory movement, wherein the damping element is adjustable, and the damping element damps an increase in the difference in height between the ski body and the binding plate more strongly than a reduction in this difference in height. 23-46. (canceled) 